Outlook 2016 Autodiscover Issues
Outlook 2016 see’s Microsoft doing away with the manual Exchange Setup. This means the only way to add an account is using the Auto Account Add feature. For this to happen it is imperative to make sure that the Auto Discover entries for your Domain are correct
We have seen examples where the autodiscover has been correct and yet the mailbox fails to add after 30-60mins of attempting to autodiscover. Through some testing, we have found that this can be circumnavigated by adding 4 registry entries.

open registry editor
Start > Run > regedit

Navigate to the following area in the registry
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\AutoDiscover\

In this location we want to create 4 new DWORD Entries by right clicking on the right pane, going to ‘New’ ‘DWORD (32-bit) Value

We then Want to add the following entries
ExcludeHttpsRootDomain
ExcludeScpLookup
ExcludeHttpRedirect
ExcludeHttpsAutoDiscoverDomain
We then need to right click on ever entry and change the value to 1 so it is on
Reboot the machine
You should now find the Auto Add feature works